Do "Mad Men," "Pan Am," "The Playboy Club" and BBC America's "The Hour" exploit society's barely suppressed appetite for a more sexist, racist and conservative era? Fear not. The underlying message in these depictions of the bad old days is clear: We should be better than that now, even when we aren't.

Just as we can enjoy "Gone With the Wind" without feeling nostalgic for slavery, or "The Sound of Music" without missing the Third Reich, we can watch the chain-smoking white men and underpaid, underappreciated women of "Mad Men" without wishing we could bring back Jim Crow racial segregation and legal glass ceilings for women.

Quite the opposite, the best moments of this surprising new nostalgia craze for the 1950s and early '60s come when they suggest glimmers of the social revolution that we, today's audience gazing back with the wisdom of hindsight, know is about to take place.